Lower Carbon Dioxide Levels Research Articles

IMPACT OF ENRICHED CO2 IN MODIFIED ATMOSPHERE PACKAGING ON THE PRESERVATION OF “PALMARITAS” STRAWBERRIES AND THE EXTENSION OF THEIR SHELF LIFE

This study evaluated the effect of modified atmospheres (MAPs) with low oxygen levels (2.5%) and high carbon dioxide levels (from 5 to 20%) on strawberries. During 12 days of storage at 4°C, various quality and chemical content parameters were evaluated. These including decay, color, weight loss, firmness, total soluble solids, total polyphenols, anthocyanins, and flavonoids, as well as antioxidant capacity and individual phenolic compounds (quercetin, caffeic acid, gallic acid, (-) epicatechin, and p-coumaric acid). Results showed that high CO2 levels had a positive impact on strawberry preservation: weight loss was reduced, anthocyanin content increased, decay and softening were significantly reduced, and vitamin C content was maintained. At the same time, these high concentrations of CO2 did not affect sugar content, color, antioxidant capacity, total phenolic compounds, or total flavonoid compounds of strawberries. A storage time of 12 days at 4°C, under MAP with an initial gas condition of 2.5% O2 + 15% CO2 + 82.5% N2 or 2.5% O2 + 20% CO2 + 77.5% N2, was found to be ideal for preserving the quality of fresh strawberries.

Identification of genes used by Escherichia coli to mitigate climatic stress conditions

IntroductionIncreasing temperature and elevated atmospheric carbon dioxide levels could impact the survival of stress-adapted bacteria. Method and resultsIn this study, RNA sequencing was performed to quantify Escherichia coli BL21 (DE3) gene expression in culture media under environmental temperature (27 °C and 42 °C) and carbon dioxide (0.2 % and 6 % v/v) conditions. Differential gene expression analysis between low temperature and different carbon dioxide conditions revealed up-regulated genes such as ldtC and bioA, optimising cell wall integrity and nutrient uptake. While, the downregulation of genes such as malK suggested a metabolic adaptation. Low temperature and high carbon dioxide levels enhanced bacterial tolerance to environmental stress. Under optimal temperatures, Escherichia coli adapts through various metabolic pathways while engaging in different processes at low temperatures and carbon dioxide levels, with temperature having a greater impact on gene expression than carbon dioxide levels. This study shows that complex metabolic activities are activated when both temperatures and carbon dioxide levels are combinsed, affecting antimicrobial resistance, nutrient acquisition, and adaptation strategies. ConclusionEach condition exhibited mechanisms to enhance cellular resilience and adaptation to stress, focusing on cellular integrity, optimising energy utilisation, and activating stress response pathways. Impact statementThe findings stress the importance of continued research to understand the implications of climate change on microbial transcriptomes comprehensively.

Low intraoperative end-tidal carbon dioxide levels are associated with improved recurrence-free survival after elective colorectal cancer surgery

Study objectiveHigher levels of carbon dioxide (CO2) increase the invasive abilities of colon cancer cells in vitro. Studies assessing target values for end-tidal CO2 concentrations (EtCO2) to improve surgical outcome after colorectal cancer surgery are lacking. Therefore, we evaluated whether intraoperative EtCO2 was associated with differences in recurrence-free survival after elective colorectal cancer (CRC) surgery. DesignSingle center, retrospective analysis. SettingAnesthesia records, surgical databases and hospital information system of a tertiary university hospital. PatientsWe analyzed 528 patients undergoing elective resection of colorectal cancer at Heidelberg University Hospital between 2009 and 2018. InterventionsNone. MeasurementsIntraoperative mean EtCO2 values were calculated. The study cohort was equally stratified into low-and high-EtCO2 groups. The primary endpoint measure was recurrence-free survival until last known follow-up. Groups were compared using Kaplan-Meier analysis. Cox-regression analysis was used to control for covariates. Sepsis, reoperations, surgical site infections and cardiovascular events during hospital stay, and overall survival were secondary outcomes. Main resultsMean EtCO2 was 33.8 mmHg ±1.2 in the low- EtCO2 group vs. 37.3 mmHg ±1.6 in the high-EtCO2 group. Median follow-up was 3.8 (Q1-Q3, 2.5–5.1) years. Recurrence-free survival was higher in the low-EtCO2 group (log-rank-test: p = .024). After correction for confounding factors, lower EtCO2 was associated with increased recurrence-free survival (HR = 1.138, 95%-CI:1.015–1.276, p = .027); the hazard for the primary outcome decreased by 12.1% per 1 mmHg decrease in mean EtCO2. 1-year and 5-year survival was also higher in the low-EtCO2 group. We did not find differences in the other secondary endpoints. ConclusionsLower intraoperative EtCO2 target values in CRC surgery might benefit oncological outcome and should be evaluated in confirmative studies.

Anterior palatoplasty as a treatment for mild and moderate obstructive sleep apnea: our experience

Abstract BACKGROUND. Obstructive sleep apnea (OSA) is characterized by frequent episodes of breathing cessation during sleep, resulting in low oxygen and high carbon dioxide levels, leading to daytime sleepnes, cognitive issues, and increased cardiovascular risk. The objective of this study was to assess the effectiveness of the anterior palatoplasty (AP) procedure in the treatment of patients with mild and moderate obstructive sleep apnea. MATERIAL AND METHODS. Sixteen patients diagnosed with mild and moderate OSA underwent AP in our clinic between 2021-2023. All patients were > 18 years old, body mass index < 30, with an apnea-hypopnea index (AHI) from 10 to 40 and disfunction of the velopharyngeal or of the retropalatal space. Patients underwent a one-night polysomnography examination prior to the surgical procedure, as well as six months after the procedure. Additionally, patients were asked to complete the Epworth Sleepiness Scale (ESS) both prior to and six months following the surgery. The procedure was done under general anaesthesia and involved AP surgery with or without reducing of the uvula. RESULTS. The average of total AHI values decreased from 28.89 per hour prior to surgery to 11.14 per hour six months after surgery. The oxygen desaturation index decreased after surgery with 2.57%. ESS scores of patients also decreased from 10.40 to 7.80 and all patients felt less tired. CONCLUSION. We believe that AP is an effective technique in the treatment of mild and moderate OSA caused by a disfunction of the velopharyngeal or retropalatal space. Additionally, we consider that AP is linked with a lower incidence of post-surgical complications compared to other surgical options.

Comparison of Recently Proposed Causes of Climate Change

This paper compares the ideas contained in the main papers published on climate change since World War II to arrive at a suggested consensus of our present knowledge regarding climatic changes and their causes. Atmospheric carbon dioxide is only suggested as a cause in one theory, which, despite its wide acceptance by Politicians, the media, and the Public, ignores the findings in other studies, including the ideas found in the Milankovitch Cycles. It also does not explain the well-known NASA map of the changes between the global 1951–1978 and the 2010–2019 mean annual temperatures. The other theories by Oceanographers, Earth scientists, and Geographers fit together to indicate that the variations in climate are the result of differential solar heating of the Earth, resulting in a series of processes redistributing the heat to produce a more uniform range of climates around the surface of the Earth. Key factors are the shape of the Earth and the Milankovitch Cycles, the distribution of land and water bodies, the differences between heating land and water, ocean currents and gateways, air masses, and hurricanes. Low atmospheric carbon dioxide levels during cold events could result in too little of this gas to support photosynthesis in plants, resulting in the extermination of most life on Earth as we know it. The 23 ka Milankovitch cycle has begun to reduce the winter insolation received at the surface of the atmosphere in the mid-latitudes of the Northern Hemisphere starting in 2020. This results in extreme weather as the winter insolation reaching the surface of the atmosphere in the higher latitudes of the Northern Hemisphere decreases while the summer air temperatures increase. It heralds the start of the next glaciation. A brief outline is given of some of the climatic changes and consequences that may be expected in western Canada during the next 11.5 ka.

Respiratory function monitoring during early resuscitation and prediction of outcomes in prematurely born infants.

Over the last decade, there has been increased use of end-tidal carbon dioxide (ETCO2) and oxygen saturation (SpO2) monitoring during resuscitation of prematurely born infants in the delivery suite. Our objectives were to test the hypotheses that low end-tidal carbon dioxide (ETCO2) levels, low oxygen saturations (SpO2) and high expiratory tidal volumes (VTE) during the early stages of resuscitation would be associated with adverse outcomes in preterm infants. Respiratory recordings made in the first 10 min of resuscitation in the delivery suite of 60 infants, median GA 27 (interquartile range 25-29) weeks were analysed. The results were compared of infants who did ordid not die or did or did not develop intracerebral haemorrhage (ICH) or bronchopulmonary dysplasia (BPD). Twenty-five infants (42%) developed an ICH and23 (47%) BPD; 11 (18%) died. ETCO2 at approximately 5min after birth was lower in infants who developed anICH, this remained significant after adjusting for gestational age, coagulopathy and chorioamnionitis (p=0.03). ETCO2 levels were lower in infants who developed ICH or died compared to those that survived without ICH, which remained significant after adjustment for gestational age, Apgar score at 10min, chorioamnionitis and coagulopathy (p=0.004). SpO2 at approximately 5min waslower in the infants who died compared to those who survived which remained significant after adjusting for the5-min Apgar score and chorioamnionitis (p=0.021). ETCO2 and SpO2 levels during early resuscitation in the delivery suite were associated with adverse outcomes.

Quality Evolution and Aroma Profile of Pointed Cabbage in Different Storage Regimes.

With its increasing popularity, the need for optimal storage conditions of pointed cabbages becomes more important to meet the year-round demand. Storage of the pointed varieties, however, is more difficult compared to the traditional, round varieties and is limited to a few weeks in normal air. Pointed cabbages are more susceptible to quality loss (shriveling, yellowing of leaves, weight loss, fungal, and bacterial infections) and tend to spoil much faster. In order to provide a year-round availability of the fresh product, storage under controlled atmosphere (CA) could offer a solution. In this study, pointed, white cabbage heads (Brassica oleracea var. capitata for. alba L. subv. Conica cv. ‘Caraflex’) were stored at 1°C from November 2018 to May 2019 under four different CA conditions (1 kPa O2 + 1.5 kPa CO2, 1 kPa O2 + 5 kPa CO2, 3 kPa O2 + 1.5 kPa CO2, and 3 kPa O2 + 5 kPa CO2), and compared to storage under normal air. Results showed that CA storage resulted in a prolonged storage life with a good quality retention for both texture and aroma. CA-stored cabbages showed less weight loss, shriveling, and yellowing. Internal quality parameters [color, soluble solids content (SSC)] were stable over the whole storage period for all objects. The aroma profiles of both the storage atmosphere and cabbage samples were impacted by storage duration. The aroma of cabbage juice was also affected by the storage regime. A clear separation was found for cabbage stored under CA compared to the reference group. From the CA-treatments studied, a combination of low oxygen (1 kPa O2) and elevated carbon dioxide levels (5 kPa CO2) showed the best results maintaining quality. Storage under CA resulted in a better resemblance to the aroma of freshly, harvested produce compared to cabbages stored in normal air.

Transcutaneous carbon dioxide monitoring during therapeutic hypothermia for neonatal encephalopathy.

In neonates with post-asphyxial neonatal encephalopathy, further neuronal damage is prevented with therapeutic hypothermia (TH). In addition, fluctuations in carbon dioxide levels have been associated with poor neurodevelopmental outcome, demanding close monitoring. This study investigated the accuracy and clinical value of transcutaneous carbon dioxide (tcPCO2) monitoring during TH. In this retrospective cohort study in neonates, agreement between arterial carbon dioxide (PaCO2) values and tcPCO2 measurements during TH was determined. TcPCO2 levels during the first 24 h of hypothermia were tested for an association with ischemic brain injury on magnetic resonance imaging (MRI). Thirty-four neonates were included. Agreement (bias (95% limits of agreement)) between tcPCO2 and PaCO2 levels was 3.9 (-12.4-20.2) mm Hg. No relation was found between the body temperature and tcPCO2 levels. TcPCO2 levels differed significantly between patients with considerable and minimal damage on MRI; after 6 h (P = 0.02) and 9 h (P = 0.04). Although tcPCO2 provided a limited estimation of PaCO2, it can be used for trend monitoring during TH. TcPCO2 levels after birth could provide an early indicator of ischemic brain injury. This relation should be investigated in large prospective studies, in which adjustments for confounders can be made. Transcutaneous carbon dioxide measurements during therapeutic hypothermia in neonates show limited accuracy similar to measurements reported in normothermic neonates and can be used for trend monitoring. Low transcutaneous carbon dioxide levels during the first 24 h were associated with considerable ischemic brain injury on MRI. The value of transcutaneous carbon dioxide measurements during the first 24 h as an indicator of considerable ischemic brain injury on MRI should be investigated in future studies, adjusting for confounders. Transcutaneous oxygen measurements during therapeutic hypothermia showed an inaccuracy that could not be related to a low body temperature.

Vertical microclimate heterogeneity and dew formation in semi-closed and naturally ventilated tomato greenhouses

The extent of the vertical microclimate heterogeneity inside a greenhouse is mostly unknown, and it can strongly affect plant production and yield quality. Tomato crop was grown in a semi-closed greenhouse equipped with horizontal ventilation and sidewall curtains, which were only opened depending on microclimate conditions; and a naturally ventilated greenhouse equipped with sidewalls curtains that were kept open. Both greenhouses had a 1,000-m2 area and a net size of 50-mesh, and were located in an arid climate zone in Israel. Vertical profiles of CO2 concentration, actual vapor pressure, air, leaf and soil temperature, net CO2 assimilation rates, stomatal conductance, and total fruit yield, fresh mass, and quality were monitored in both greenhouses for 13 days, in January 2018; CO2 concentration, actual vapor pressure, and air and soil temperature were additionally monitored in the semi-closed greenhouse for seven days in December 2016, when the ventilation was inoperative, and in December 2017, with ventilation. The vertical air temperature gradient, along with the colder microclimate inside the naturally ventilated greenhouse, led to a lack of plant uniformity and yield loss. Closing the side curtains in the fanned semi-closed greenhouse had a beneficial effect on yield, however, with mixed results for quality, due to the higher air temperature and lower carbon dioxide levels at the upper canopy. Horizontal air circulation in the semi-closed greenhouse increased transpiration and assimilation, and increased dew occurrence at night, but did not reduce the vertical heterogeneity. Significant vertical gradients affect plant physiology, and closing the curtains in winter cultivation in semi-arid/arid climates has the potential to improve fruit yield and quality. However, it must be coupled with proper air circulation and, preferably, with CO2 enrichment, or careful management of natural ventilation through side curtains, in order to maximize CO2 replenishment while minimizing heat losses.

Comparison of different end-tidal carbon dioxide levels in preventing postoperative nausea and vomiting in gynaecological patients undergoing laparoscopic surgery

The aim of this study was to compare different end-tidal carbon dioxide (EtCO2) levels to prevent postoperative nausea and vomiting (PONV) caused by increased intracranial pressure due to pneumoperitoneum and Trendelenburg position in gynaecological laparoscopic surgery. A total of 60 female patients aged 25–50 years who would undergo laparoscopic gynaecological surgery under general anaesthesia were randomised into two groups: group A (EtCO2: 26 − 35 mmHg, n = 30) and group B (EtCO2: 36 − 45 mmHg, n = 30). In both groups, ONSD and EtCO2 of the patients were measured at baseline after anaesthesia induction (T b), at 5 min after pneumoperitoneum (T PP5), and at 10 min intervals after Trendelenburg position (T PP10, T PP20, T PP30). At 5 (T D5) and 10 min (T D10) after deflation, ONSD measurements were repeated. The incidence and severity of PONV of the patients, and antiemetic drugs used in both groups were assessed in the postoperative period. In the intraoperative follow-up periods, T PP5 and subsequent EtCO2 values, as well as T PP10 and subsequent ONSD values, were significantly higher in group B and the incidence of nausea, the PONV scores and the incidence of rescue antiemetic use significantly lower in group A than in group B (p<.001 for all). This result indicates that low EtCO2 levels have beneficial effects on ICP and PONV in laparoscopic gynaecological operations. Impact statement What is already known on this subject? Laparoscopic gynaecologic surgery has been a more preferred technique. The incidence of postoperative nausea and vomiting (PONV) after laparoscopic gynaecologic surgery is remarkably high. In the prevention of PONV after gynaecologic laparoscopic surgery, single and multiple drug therapies and methods have been used. What the results of this study add? Postoperative nausea and vomiting caused by intracranial pressure (ICP) increase due to carbon dioxide pneumoperitoneum and Trendelenburg position in gynaecologic laparoscopic surgeries were decreased in the early postoperative period by low end-tidal carbon dioxide levels in the intraoperative period. It was shown that low end-tidal carbon dioxide levels have beneficial effects on ICP and PONV in laparoscopic gynaecologic operations. What the implications are of these findings for clinical practice and/or further research? This result indicates that low end-tidal carbon dioxide levels have beneficial effects on ICP and PONV in laparoscopic gynaecologic operations.

Occurrence and Distribution of Aflatoxin in Maize from Selected Counties, Eastern Region, Kenya

Purpose: The study aimed to assess the occurrence and distribution of aflatoxin contamination on dry maize in different types of stores in Meru, Embu, Isiolo, Makueni and Machakos Counties of Eastern region of Kenya.Methodology: Automatic spear sampler was used to collect maize samples from each bag at even intervals. 280 maize samples were collected from 29 stores in five Counties. 100 g of each maize sample was ground, resampled into 50g, blended, extracted, centrifuged, filtered and a quantified for Aflatoxin B1, B2, G1 and G2. Samples were prepared and extracted with methanol/water. The bulky of the samples were analyzed with enzyme-linked immunoassay test kits. Confirmation of positive samples was done with high performance liquid chromatography (HPLC) coupled with fluorescence detector. Data analysis was done with SPSS and Microsoft excel.Findings: Maize samples from Counties in eastern region of Kenya had significantly high levels of (93.10%) aflatoxin contamination. The mean values for aflatoxin B1, B2, G1 and G2 were: 50.08± 4.42, 17.26±1.08, 30.17±2.06 and 10.54± 1.52 (ng/g) in that order. Only nine samples had total aflatoxin within the accepted limit for human consumption of 15 ng/g. The highest total aflatoxin contamination recorded was 198.45ng/g in Makueni county and the lowest recorded was 8.76ng/g in Embu county. Makueni and Embu had mean values for aflatoxin B1, B2, G1 and G2 being (83.07±7.53, 22.15± 1.36, 49.38±3.11, 20.52± 0.70 ng/g) and (18.71 ±2.63, 8.07 ±0.64, 17.02 ±1.38, 8.86 ±1.62 ng/g). Makueni NCPB depot had the highest mean contamination with aflatoxin B1 of 92.67± 5.78 ng/g and Embu had the lowest with 6.26 ± 4.14 ng/g. All the county markets recorded high aflatoxin B1 contamination with exception of Embu county which had a mean of 4.0 ±0.84, Makueni (83.67± 10.42 ng/g), Isiolo (51.27± 32.29 ng/g), Meru (46.02± 23.88 ng/g) and Machakos (36.34± 26.27 ng/g). The stores had aflatoxin load varied from on store to the other and county to county.Unique contribution to theory, policy and practice: The counties in the region had high occurrence and distribution of aflatoxin B1, B2, G1 and G2 in maize in all stores where samples were picked. Location for maize stores should be in areas with low levels of carbon dioxide because mycotoxins are produced under aerobic conditions. The design for maize threshing machines should not course shocks, breakage and cracks on maize grains to decrease chances of mycotoxins infestation during their storage.

Acetazolamide, Nifedipine and Phosphodiesterase Inhibitors: Rationale for Their Utilization as Adjunctive Countermeasures in the Treatment of Coronavirus Disease 2019 (COVID-19).

Effective treatments for Coronavirus Disease 2019 (COVID-19) outbreak are urgently needed. While anti-viral approaches and vaccines are being considered immediate countermeasures are unavailable. The aim of this article is to outline a perspective on the pathophysiology of COVID-19 in the context of the currently available clinical data published in the literature. This article appreciates clinical data published on COVID-19 in the context of another respiratory illness - high altitude pulmonary edema (HAPE). Both conditions have significant similarities that portend pathophysiologic trajectories. Following this potential treatment options emerge.Both COVID-19 and HAPE exhibit a decreased ratio of arterial oxygen partial pressure to fractional inspired oxygen with concomitant hypoxia and tachypnea. There also appears to be a tendency for low carbon dioxide levels in both as well. Radiologic findings of ground glass opacities are present in up to 86% of patients with COVID-19 in addition to patchy infiltrates. Patients with HAPE also exhibit patchy infiltrates throughout the pulmonary fields, often in an asymmetric pattern and CT findings reveal increased lung markings and ground glass-like changes as well. Widespread ground-glass opacities are most commonly a manifestation of hydrostatic pulmonary edema. Similarly, elevated fibrinogen levels in both conditions are likely an epiphenomenon of edema formation rather than coagulation activation. Autopsy results of a COVID-19 fatality revealed bilateral diffuse alveolar damage associated with pulmonary edema, pro-inflammatory concentrates, and indications of early-phase acute respiratory distress syndrome (ARDS). HAPE itself is initially caused by an increase in pulmonary capillary pressure and induces altered alveolar-capillary permeability via high pulmonary artery hydrostatic pressures that lead to a protein-rich and mildly hemorrhagic edema. It appears that COVID-19 and HAPE both discretely converge on ARDS. In light of this, a countermeasure that has been shown to be effective in the analogous condition of HAPE is Acetazolamide. Acetazolamide has a myriad of effects on different organ systems, potently reduces hypoxic pulmonary vasoconstriction, improves minute ventilation and expired vital capacity. Other therapeutics to consider that are also directed towards decreased pulmonary pressure include Nifedipine and Phosphodiesterase inhibitors.This review describes COVID-19 in parallel to HAPE. Deranged respiratory parameters that are present in both conditions are highlighted. The utilization of medications found to be effective in HAPE, for the treatment of COVID-19, is proposed. Given the medical emergency of a growing contagion and the thousands of lives at stake, expedient attempts to improve survival are needed. Acetazolamide, Nifedipine and Phosphodiesterase inhibitors may be potential countermeasures.

Effects of hypoxia/hypercapnia on the metablism of Callosobruchus chinensis (L.) larvae

Insects that are pests of stored products are highly tolerant to low O2 levels (hypoxia) and high carbon dioxide levels (hypercapnia) for long periods, but the underlying mechanism remains unclear. In the present study, we investigated the metabolic profiles of Callosobruchus chinensis (L.) larvae held under 2% O2+18% CO2 (both v/v) for 24, 48, and 96 h using gas chromatography–time-of-flight mass spectrometry (GC-TOF-MS), their corresponding control groups under normoxia were also investigated simultaneously. We found that the relative quantity of 91, 24, and 48 metabolites were altered at these three time periods, respectively. The metabolites were principally carbohydrates, organic acids, amino acids, and free fatty acids, 30 of these metabolites with high accuracy of qualitative identification and biological functions were chosen for further analyses. These were intermediates of the citric acid cycle, glycolysis, fatty acid synthesis, and amino acid metabolism. Based on our results, levels of organic acids increased, while levels of amino acids decreased, suggesting that metabolism was shifting from aerobic to anaerobic. Lipid metabolism may be relatively less important; the number of fatty acids exhibiting significant changes in level was quite small. The metabolic profiles changed dynamically over time, with the largest changes evident for 24 h of hypoxia/hypercapnia, followed by 96 h, and only a little change has been shown on 48 has revealed by heatmap and pathway topological analysis. Therefore, we present direct evidence that the metabolism of insect pests of stored products is influenced by complex environmental stressors.

Glacial expansion of oxygen-depleted seawater in the eastern tropical Pacific.

Increased storage of carbon in the oceans has been proposed as a mechanism to explain lower concentrations of atmospheric carbon dioxide during ice ages; however, unequivocal signatures of this storage have not been found1. In seawater, the dissolved gases oxygen and carbon dioxide are linked via the production and decay of organic material, with reconstructions of low oxygen concentrations in the past indicating an increase in biologically mediated carbon storage. Marine sediment proxy records have suggested that oxygen concentrations in the deep ocean were indeed lower during the last ice age, but that near-surface and intermediate waters of the Pacific Ocean-a large fraction of which are poorly oxygenated at present-were generally better oxygenated during the glacial1-3. This vertical opposition could suggest a minimal net basin-integrated change in carbon storage. Here we apply a dual-proxy approach, incorporating qualitative upper-water-column and quantitative bottom-water oxygen reconstructions4,5, to constrain changes in the vertical extent of low-oxygen waters in the eastern tropical Pacific since the last ice age. Our tandem proxy reconstructions provide evidence of a downward expansion of oxygen depletion in the eastern Pacific during the last glacial, with no indication of greater oxygenation in the upper reaches of the water column. We extrapolate our quantitative deep-water oxygen reconstructions to show that the respired carbon reservoir of the glacial Pacific was substantially increased, establishing it as an important component of the coupled mechanism that led to low levels of atmospheric carbon dioxide during the glacial.

O26-3 - Influence of Low Admission Levels of Arterial Carbon Dioxide on Clinical Outcomes in Patients with Acute Decompensated Heart Failure

O26-3 - Influence of Low Admission Levels of Arterial Carbon Dioxide on Clinical Outcomes in Patients with Acute Decompensated Heart Failure

The naked mole-rat exhibits an unusual cardiac myofilament protein profile providing new insights into heart function of this naturally subterranean rodent.

The long-lived, hypoxic-tolerant naked mole-rat well-maintains cardiac function over its three-decade-long lifespan and exhibits many cardiac features atypical of similar-sized laboratory rodents. For example, they exhibit low heart rates and resting cardiac contractility, yet have a large cardiac reserve. These traits are considered ecophysiological adaptations to their dank subterranean atmosphere of low oxygen and high carbon dioxide levels and may also contribute to negligible declines in cardiac function during aging. We asked if naked mole-rats had a different myofilament protein signature to that of similar-sized mice that commonly show both high heart rates and high basal cardiac contractility. Adult mouse ventricles predominantly expressed α-myosin heavy chain (97.9±0.4%). In contrast, and more in keeping with humans, β myosin heavy chain was the dominant isoform (79.0± 2.0%) in naked mole-rat ventricles. Naked mole-rat ventricles diverged from those of both humans and mice, as they expressed both cardiac and slow skeletal isoforms of troponin I. This myofilament protein profile is more commonly observed in mice in utero and during cardiomyopathies. There were no species differences in phosphorylation of cardiac myosin binding protein-C or troponin I. Phosphorylation of both ventricular myosin light chain 2 and cardiac troponin T in naked mole-rats was approximately half that observed in mice. Myofilament function was also compared between the two species using permeabilized cardiomyocytes. Together, these data suggest a cardiac myofilament protein signature that may contribute to the naked mole-rat's suite of adaptations to its natural subterranean habitat.

Toxicity of propylene oxide alone and in combination with low pressure or carbon dioxide against life stages of Ephestia cautella (Walker) (Lepidoptera: Pyralidae) under laboratory conditions

A series of tests was carried out in the laboratory for comparison of the insecticidal effect of propylene oxide (PPO) alone and in combination with low pressure and/or elevated levels of carbon dioxide against eggs, larvae, pupae and adults of Ephestia cautella (Walker) (Lepidoptera: Pyralidae). All life stages of E. cautella were exposed to PPO alone and in combination with either a low pressure of 100 mm Hg or 92% CO2 for 4 h at 26 ± 1 °C and 65 ± 5% relative humidity (r.h.). The results indicated that PPO alone was moderately effective with concentration x time products (Ct products) required to obtain 99% mortality of the different life stages of E. cautella ranging between 66.1 and 536.2 mg h/L. The life stages differed in their susceptibility to PPO. Eggs were the most susceptible with a LC99 value of 16.5 mg/L, whereas pupae were the most tolerant with a LC99 value of 134.1 mg/L. Mortality of all life stages was extremely low (1.3–18.8%), when exposed to either the low pressure or 92% CO2 alone for 4 h. However, when low pressure or 92% CO2 were combined with PPO, the LC50 and LC99 values for all stages of E. cautella were notably reduced. Combination of PPO with low pressure or 92% CO2 caused reductions in the LC99 values for all life stages, compared with those exposed to PPO alone. These results indicated that low pressure (100 mm Hg, equals to 13,332 Pa or 0.13 atm) and 92% CO2 clearly increased the efficacy of PPO to E. cautella. By considering the overall insecticidal efficacy data, the combination of PPO with low pressure was, in all cases, more effective than the combination of PPO with CO2.

Neurophysiological Evidence for a Cortical Contribution to the Wakefulness-Related Drive to Breathe Explaining Hypocapnia-Resistant Ventilation in Humans.

Human ventilatory activity persists, during wakefulness, even when hypocapnia makes it unnecessary. This peculiarity of human breathing control is important to speech and speech-breathing insofar as speech induces hypocapnia. This study evidences a specific respiratory-related cortical activity. This suggests that human hypocapnic breathing is driven, at least in part, by cortical mechanisms similar to those involved in volitional breathing, in breathing against mechanical constraints or with weak inspiratory muscle, and in patients with defective medullary breathing pattern generators. This fuels the notion that the human ventilatory drive during wakefulness often results from a corticosubcortical cooperation, and opens new avenues to study certain ventilatory and speech disorders.

Traumatic brain injury: physiological targets for clinical practice in the prehospital setting and on the Neuro-ICU.

Over many years, understanding of the pathophysiology in traumatic brain injury (TBI) has resulted in the development of core physiological targets and therapies to preserve cerebral oxygenation, and in doing so prevent secondary insult. The present review revisits the evidence for these targets and therapies. Achieving oxygen, carbon dioxide, blood pressure, temperature and glucose targets remain a key goal of therapy in TBI, as does the role of effective prehospital care. Physician led air ambulance teams reduce mortality. Normobaric hyperoxia is dangerous to the injured brain; as are both high and low carbon dioxide levels. Hypotension is life threatening and higher targets have now been suggested in TBI. Both therapeutic normothermia and hypothermia have a role in specific groups of patients with TBI. Although consensus has not been reached on the optimal intravenous fluid for resuscitation in TBI, vigilant goal-directed fluid administration may improve outcome. Osmotherapeutic agents such as hypertonic sodium lactate solutions may also have a role alongside conventional agents. Maintaining physiological targets in several areas remains part of protocol led care in the acute phase of TBI management. As evidence accumulates however, the target values and therefore therapies may be set to change.

Análise da eficiência energética nos países do BRICS: um estudo envolvendo a Análise por Envoltória de Dados

Resumo Num período de mudanças climáticas e restrições a emissões cada vez maiores, é importante focar o desenvolvimento das nações na direção de uma economia de baixo carbono. Neste contexto, o crescimento do consumo de energia tornou-se um problema grave; logo, medidas que garantam a eficiência energética tornaram-se prioritárias para qualquer nação que esteja disposta a desenvolver sua economia. Considerando que o grupo do BRICS tem apresentado rápido desenvolvimento econômico e desempenhado importante papel na economia mundial, este trabalho teve como principal objetivo medir e analisar a eficiência energética total de fatores nos países que compõem o BRICS (Brasil, Rússia, Índia, China e África do Sul), propiciando informações sobre países benchmark dentro desse grupo e sobre como o Brasil se encontra nesse cenário. Para isso, foi utilizada a Análise Envoltória de Dados (DEA), modelo SBM variante e análise de janela, e, a partir das folgas fornecidas por esta ferramenta, foi calculado o índice de eficiência energética total de fatores (EETF) para os países analisados. Como inputs foram utilizados a formação bruta de capital fixo, trabalho e consumo energético e como outputs, a emissão de CO2 (output indesejável) e o Produto Interno Bruto – PIB (output desejável). A partir dos resultados, observou-se que o Brasil é o país com melhor índice de EETF dentro do BRICS, seguido por África do Sul, China, Índia e Rússia.